Field of the Invention
The present invention relates to a fixing member to be used in a heat-fixing device of an electrophotographic image forming apparatus, a method of manufacturing the fixing member, a fixing device, and to an image forming apparatus.
Description of the Related Art
As a fixing member to be used in a heat-fixing device of an electrophotographic image forming apparatus such as a printer, a copying machine, or a fax machine, there is given a fixing member having a film shape or a roller shape. As such fixing member, there has been known a fixing member that includes a film-shaped or roller-shaped base member made of a heat-resistant resin or a metal, an elastic layer made of a heat-resistant rubber or the like formed on the base member, as necessary, and a surface layer containing a fluororesin having an excellent releasability with respect to toner. In this case, as the fluororesin to be contained in the surface layer, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) excellent in heat resistance is preferably used.
Meanwhile, in recent years, the durability required of the fixing member tends to increase further along with an increase in printing speed. The fluororesin layer on a surface of the fixing member is chipped due to abrasion between the fluororesin layer and paper, and hence the durability of the fixing member is secured through the thickness of the fluororesin layer. Therefore, in order to increase the durability of the fixing member, a large number of studies for improving abrasion resistance of the fluororesin layer have been conducted.
In Japanese Patent Application Laid-Open No. 2010-181621, which discloses the invention relating to a non-rotary pressing member arranged on a fixing unit of an electrophotographic image forming apparatus, it is disclosed that the abrasion resistance of a crosslinked fluororesin layer formed through Steps 1 to 4 is significantly improved.
Step 1 of forming an unbaked and uncrosslinked fluororesin layer on a base member;
Step 2 of baking the fluororesin layer by heating the fluororesin layer at a temperature within a range of from a melting point (Tm) of the fluororesin to a temperature higher by 150° C. than the melting point thereof (Tm+150° C.);
Step 3 of adjusting the temperature of the baked uncrosslinked fluororesin layer at a temperature within a range of from a temperature lower by 50° C. than the melting point of the fluororesin (Tm−50° C.) to a temperature higher by 50° C. than the melting point thereof (Tm+50° C.); and
Step 4 of crosslinking an uncrosslinked fluororesin by irradiating the uncrosslinked fluororesin layer adjusted for temperature with a radiation having a radiation dose within a range of from 1 to 1,000 kGy in an atmosphere having an oxygen concentration of from 0.1 to 1,000 ppm.
In addition, in Japanese Patent Application Laid-Open No. 2010-181621, as specific examples of the fluororesin, there are given polytetrafluoroethylene (PTFE), a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and a tetrafluoroethylene-hexafluoropropylene copolymer (FEP).